# US 7,411,597 B2 · Image forming apparatus

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- Number: US 7,411,597 B2
- Document ID: US7411597B2
- Status: Granted
- Kind: B2
- Application number: 11/745,649
- Filed: 2007-05-08
- Published: 2007-11-22
- Granted: 2008-08-12
- Earliest claimed: 2006-05-16
- Assignees: Canon Kabushiki Kaisha
- Inventors: Junichi Noguchi; Katsumi Takahashi
- Web page: https://patentgrep.com/patent/US7411597B2

## CPC

- G03G 15/0131: {for transferring a pattern to a second base}
- G03G 2215/0119: Linear arrangement adjacent plural transfer points
- G03G 2215/0161: Generation of registration marks
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An image forming apparatus includes an intermediate transfer member position detection unit configured to detect a position of the intermediate transfer member to output an image forming operation start signal, a pattern detection unit configured to detect a registration correction pattern formed on the intermediate transfer member based on the image forming operation start signal, a misregistration variation detection unit configured to read the registration correction pattern detected by the pattern detection unit based on the image forming operation start signal and to generate a reference clock signal based on the read registration correction pattern, and a polygonal mirror drive motor control unit configured to adjust a rotation speed of the polygonal mirror drive motor based on the reference clock signal generated by the misregistration variation detection unit.

## Claims

### Claim 1

An image forming apparatus comprising:
an image carrier;
a polygonal mirror drive motor configured to drive a polygonal mirror to scan the image carrier with a laser beam emitted from a light source;
an intermediate transfer member configured to transfer thereto a toner image formed on the image carrier;
a drive roller configured to drive the intermediate transfer member, wherein a perimeter of the intermediate transfer member is substantially an integral multiple of a perimeter of each of the image carrier and the drive roller;
an intermediate transfer member position detection unit configured to detect a position of the intermediate transfer member to output an image forming operation start signal;
a pattern detection unit configured to detect a registration correction pattern formed on the intermediate transfer member based on the image forming operation start signal;
a misregistration variation detection unit configured to read the registration correction pattern detected by the pattern detection unit based on the image forming operation start signal and to generate a reference clock signal based on the read registration correction pattern; and
a polygonal mirror drive motor control unit configured to adjust a rotation speed of the polygonal mirror drive motor based on the reference clock signal generated by the misregistration variation detection unit.

### Claim 2 (depends on 1)

The image forming apparatus according to claim 1, wherein the registration correction pattern includes a first registration correction pattern for correcting a stationary misregistration and a second registration correction pattern for correcting a periodic misregistration.

### Claim 3

An image forming apparatus comprising:
a plurality of image carriers;
a plurality of polygonal mirror drive motors each configured to drive a polygonal mirror to scan each image carrier with a laser beam emitted from a light source image;
an intermediate transfer member configured to transfer thereto a toner image formed on each image carrier;
a drive roller configured to drive the intermediate transfer member, wherein a perimeter of the intermediate transfer member is substantially an integral multiple of a perimeter of each of the plurality of image carriers and the drive roller;
an intermediate transfer member position detection unit configured to detect a position of the intermediate transfer member to output an image forming operation start signal;
a pattern detection unit configured to detect a registration correction pattern formed on the intermediate transfer member based on the image forming operation start signal;
a misregistration variation detection unit configured to read the registration correction pattern detected by the pattern detection unit based on the image forming operation start signal and to generate a reference clock signal based on the read registration correction pattern; and
a polygonal mirror drive motor control unit configured to adjust a rotation speed of each of the plurality of polygonal mirror drive motors based on the reference clock signal generated by the misregistration variation detection unit.

### Claim 4 (depends on 3)

The image forming apparatus according to claim 3, wherein the registration correction pattern includes a first registration correction pattern for correcting a stationary misregistration and a second registration correction pattern for correcting a periodic misregistration.

### Claim 5

An image forming apparatus comprising:
an image carrier;
a polygonal mirror drive motor configured to drive a polygonal mirror to scan the image carrier with a laser beam emitted from a light source;
a transfer material conveying member;
a drive roller configured to drive the transfer material conveying member, wherein a perimeter of the transfer material conveying member is substantially an integral multiple of a perimeter of each of the image carrier and the drive roller;
a transfer material conveying member position detection unit configured to detect a position of the transfer material conveying member to output an image forming operation start signal;
a pattern detection unit configured to detect a registration correction pattern formed on the transfer material conveying member based on the image forming operation start signal;
a misregistration variation detection unit configured to read the registration correction pattern detected by the pattern detection unit based on the image forming operation start signal and to generate a reference clock signal based on the read registration correction pattern; and
a polygonal mirror drive motor control unit configured to adjust a rotation speed of the polygonal mirror drive motor based on the reference clock signal generated by the misregistration variation detection unit.

### Claim 6 (depends on 5)

The image forming apparatus according to claim 5, wherein the registration correction pattern includes a first registration correction pattern for correcting a stationary misregistration and a second registration correction pattern for correcting a periodic misregistration.

### Claim 7

An image forming apparatus comprising:
a plurality of image carriers;
a plurality of polygonal mirror drive motors each configured to drive a polygonal mirror to scan each image carrier with a laser beam emitted from a light source image;
a transfer material conveying member;
a drive roller configured to drive the transfer material conveying member, wherein a perimeter of the transfer material conveying member is substantially an integral multiple of a perimeter of each of the plurality of image carriers and the drive roller;
an transfer material conveying member position detection unit configured to detect a position of the transfer material conveying member to output an image forming operation start signal;
a pattern detection unit configured to detect a registration correction pattern formed on the transfer material conveying member based on the image forming operation start signal;
a misregistration variation detection unit configured to read the registration correction pattern detected by the pattern detection unit based on the image forming operation start signal and to generate a reference clock signal based on the read registration correction pattern; and
a polygonal mirror drive motor control unit configured to adjust a rotation speed of each of the plurality of polygonal mirror drive motors based on the reference clock signal generated by the misregistration variation detection unit.

### Claim 8 (depends on 7)

The image forming apparatus according to claim 7, wherein the registration correction pattern includes a first registration correction pattern for correcting a stationary misregistration and a second registration correction pattern for correcting a periodic misregistration.